The dispute over the top job surfaced once again as both parties launched their election manifestos yesterday.

Mr Adams said Martin McGuinness was already Mr Robinson's equal in the joint office of First Minister and deputy First Minister.

The DUP leader said the more senior title had symbolic and political significance.

Mr Robinson also rejected Mr McGuinness's offer to consider changing the title of the posts to ‘joint First Minister’ if he emerged from the May 5 Assembly poll in the lead position.

The DUP leader said the offer from Mr McGuinness was merely an “electoral tactic” and insisted his party would press for the top job.

“There is a status difference, indeed the name itself is a bit of a clue that there is a difference between the two,” the DUP leader said.

While the First Minister title goes to the biggest party, Mr Robinson said it was important to note that this also signalled the privilege of first choice of Executive departments and greater Assembly voting strength. “It is vital that we keep the DUP ahead,” he said.

Mr Adams said: “First of all, we have to spell out again, the Office of First Minister and Deputy First Minister: they're like Siamese twins.

“They are co-equal positions, with exactly the same power and authority as the other.”

The Sinn Fein president agreed the post was of symbolic significance, but he said that meant nothing to people who were unemployed or in need of health services, and who wanted Government to focus on those issues.

“I simply see this as a tactic by the DUP to try and galvanise unionist support for their position, based upon this negative,” said Mr Adams.

“Politics has to be about positivity. Politics has to be about hope. Politics has to be about the future.

“So, we'll focus on the real issues,” he added.

“And it is within the gift of the electorate who will take up these departmental responsibilities.”